This proposal addresses itself to the study of the brain mechanisms involved in visual pattern recognition and perception. Recently, we have discovered that it is possible to actually control the development of functional properties of single cells in the visual cortex of kittens by the simple device of controlling their visual experience. We have succeeded in demonstrating that "shape" of all committed visual receptive fields in the visual cortex of controlled experience kittens is directly related to the shape of the visual stimuli they viewed during development. For some units the receptive field shape is arecognizable, though blurred, image of the stimulus! These findings form the bases for the proposed experiments. We intend to raise kittens in environments designed to engage different, specific aspects of visual perception. We expect that the kittens will have cells where functional characteristics will relate to specific features of the experience. This will enable us to relate function with mechanisms directly. We will further attempt to idenitfy inborn versus experientially determined properties of single cells and networks. Finally, we will direct our investigation at measuring and tracing connectivity of cells whose properties have been engendered by controlled experinces.